peebles



July 3, 1928.

T. A. PEEBLEQ;

APPARATUE FOR CONTROLLING STEAM GENERATION Filed July 22, 1926 4 Sheets-Sheet A MN July 3, 1928. l.675,8l8

Filed July 22, 1926 4 Sheets-Sheet 2 TO STEAM LINE A x/wavroxa July 3, 1928. Y 1,675,818

T. A. PEEBLES I APPARATUS FOR CONTROLLING STEAM GENERATION Filed July 22, 1926 4 Sheets-$1861. 3

INVIYTOR T. A. PEEBLES APPARATUS FOR CONTROLLING STEAM GENERATION" July 3, 1928. ,675,818

Filed July 22, 1926 4 Shepts-Sheet 4 glwuomtoz Patented July 3,1928.

f UNITED STATES PATENT OFFICE.

THOMAS A. renews, or PITTSBURGH, PENNSYLVANIA, Assmnon To JOHN m.

norwoon, or noemolv'r, PEN SYLVANIA. I

APPARATUS FOR eoiv'moLLme STEAM GENERATION.

Application meann' 22;

has for an object to produce a system of automatic control which proportions the delivery of fuel to a steam boiler in accordance with the demand for steam, and which malntalns a predetermined standard of combustion, within the boiler furnace, for

all varying rates of fuel feed.

A further object is to produce a control system for steam boilers which is automatic in response to variations in steam conditions Y and' in which the delivery of fuel and air to the boiler furnace is proportioned to the varying steam conditions, but the delivery of air is so modified by the varying furnace conditions so as to maintain a predetermined standard of combustion conditions within the furnace for all rates of fuel feed to the furnace. i

A further object is to produce a system of control for a plurality of steam boilers delivering steam to a single header in which automatic means are employed for proportioning the delivery of fuel to all the boilers in response tovariations in the demand for steam or similar conditions within the header, and in which means are also employed for varying. the delivery of air in response to steam conditions but in so modifying the delivery of 'air to each boiler furnace in response to the conditions therein encountered as to maintain a predetermined standard of combustion conditions in each individual boiler furnace for each rate of fuel feed.

A further object is to produce an auto matic control system .for a. plurality of. boilers delivering steam to a single header, in which a master regulator is employed. for

varying automatically controlling the operation of' all the boiler furnaces included in the system and in connection with which means are employed for varying theuoperation of the master regulator so that conditions throughout the entire system may be varied, even while the system is'responding to the automatic operation of the master regulator.

A further object is to produce a system of control for aplurality of boilersconstituting a unitary source of steam supply, in which automatic means are employed for controlling the operation of the individual furnaces of each of the boilers in respond- 1926:: Serial No. 124348;

mg to varying steam conditions and in which means are employed for adjusting the automatic regulation for each individual furnace so that individual regulation of each furnace may be accomplished While all or some of the other furnaces of the system are automatically controlled.

These and other objects, Which will be 'made more apparent throughout the further description of the invention, are attained by means of the apparatus herein set forth and the method of control herein described.

In the drawingsi 1 t Figure 1 is a diagrammatic View of a control system embodying my invention;

Fig. 1* is a fragmental sectional View of a detail of the apparatus;

Fig. 2 is a detail view of a master regula tor which may be employed asa part of the control system illustrated in Fig. 1; and

Fig. 3 is a diagrammatic vieWo't a pertionof the controlsystem shown in Fig. 1,

Flg. 4 is a diagrammatic view illustrating a hattery of boiler furnaces provided with a control system arran ed-in accordance with ,one embodiment of tus invention.

The apparatus herein illustrated islmore particularly adapted to controlthe operation of a plurality ofboilers whereinall of the boilers cooperate to deliveiusteami to a single steam line orheader. In such installations, it is essential to maintain a predetermined standard of combustion conditions Within each furnace and to proportion thedelivery of fuelto the furnaces of the 1 Ild1\'1dl1t]l boilers in response to the demand for steam placed up'on all the co-operating boilers.

in the illustrated embodiment of my invention, I have accomplished this by vary: ing the fuel supply to all the boiler furnaces in response to variations in steam pressure .VVltlllIl the steam header fed by all the boilers and I thenproportion the delivery of air to each :individual furnace so @as to maintain an air. supply to each furnace which is proportional to the rate .ofwfuel feed thereto but which is responsive to the varying conditions Within the furnace. and the gas'outlet passages of the furnace.

In addition, I have provided a control system for controlling the fuel feed and air delivery to all the furnaces included within the system, which is responsive to a master regulator, but I have also employed what may be termed a primary regulator for each furnace of the group which may be adjusted so as to operate in response to the master regulator but at the same time vary the cited of the automatic control to each indi-' the boilers of the group and the automatic,

regulation is thereby rendered more efiective in maintaining the standard conditions under all the variables encountered in the operation of a boiler plant.

In Fig. 1, I have diagrammatically illustrated the control system in connection with but one boiler of a group of boilers, but it will be understood that the master regulator 6 is operatively connected to a plurality of primary regulators 7, one of which is employed for each boiler of the group.

The system is also illustrated in the form it would be employed for controlling a plurality of boilers fired with powdered fuel, but it, will be apparent to those skilled in the art that the system with slight modifications may be'employed for controlling the operation of stoker, or gas, or oil-fired boiler furnaces.

.As illustrated, the master regulator 6 is provided with a pressure responsive member which is located in a pressure chamber 8 and is operatively connected to a lever 9 so arranged that its movements, in response to varying steam pressure, control the operation of a pressure actuated relay mechanism 10. The arrangement being such that the plunger of the relay and, consequently, the cross-head 11 operatively connected thereto, will occupy definite positions for the dit-' ferent positions of the lever 9. It will be understood that the pressure chamber 8 is connected to the steam header or steam line which receives steam fromthe various boilers of the group tobe controlled, and that the pressure therein varies with the steam pressure. As indicated, the piping 12 communicates with this steam header.

I have provided simple and effective means for communicating the effect of the movement of the relay cross-head 11 to the .able link from a lever 11, fulcrumed at 11' control mechanism of the various boilers of,

the group. .As illustrated, I employ an inverted bell 13, which is suspended by a suitand which is actuated by the cross-head 11. The lower edge of this bell'projects into liquid, such as water, oil or mercury, which is contained within a receptacle 13. Air under pressure from a suitable source is delivered to the interior of the bell through piping 13 which projects through the bottom of the receptacle and well above the surface of the liquid,-terrninating within the bell 13. This piping may be rovided with a control valve 13 for control ing the rate of air flow into the bell. A second piping 14 projects up through the bottom 0 the receptacle 13 into the bell and is in open communication with the interior of the bell. This piping communicates with each of the primary regulators, 7, one of which is preferably provided for each boiler included in the system.

It will be apparent that variations in stcan'r pressure communicated to the pressure chamber 8 will occasion variations in the position of the cross-head 11, by reason of the operation of the lever 9, and consequently the bell 13 will be moved to diflt'erent elevations, so that its lower edge is more or less eti'ectively sealed by the liquid contained within the receptacle 13, depending upon the amount of submergence of the lower edge of the bell. The source of air pressure with which the supply piping 13 communicates is maintained at a. higher pressure than can be sealed by the liquid in the receptacle 13 no matter what position the bell 13 occupies with relation to the surface of that liquid. Consequently, during the normal operation of the apparatus, there will be a leakage of air from the interior of the'bell around its lower edges and the pressure within the bell will respond to, and depend upon the position of the hell; or in other words, upon the head of sealing liquid maintained above the edge of the bell.

it-h such an arrangement, the pressure within the bell will vary as the bell moves to different positions and consequently this pressure will vary directly with the steam pressure in the header as transmitted to the pressure chamber 8, with the result that the controlling pressure transmitted to all of the primary regulators 7 through the piping 14 will vary in accordance with the steam pressure.

While I prefer to control the master reg- 1921, and a fuller description thereof is therefore deemed unnecessary.

I have also shown the master regulator operatively coupled to an indicator 15 by means of a flexible cord in such a way as to move the hand of the indicator to diiferent positions around the indicator dialfor the through the purpose of visually indicatingthe pressure within the steam header. I have also illus trated a manual control for the lever 9 which consists of a bracket 16 provided'with oppositely positioned thumb screws 16", adapted to engage opposite sides of the lever and thereby hold it in any definite adjusted position. It will be apparent that during the automatic operation of the apparatus, the thumb screws'lG will be moved out of contact with the lever 9 and to such positions that they donot interfere with its swing. I have also shown the lever as counterbalanced by adjustable weights17 which are so a-r'anged that the counterbalancing of the steam pressure Within the chamber 8 may be varied so asto-eifect or vary the automatic operation as occasioncd by varia ions in this steam pressure.

In the dra-Wings,I have illustrated but? one of the primary regulators, which is generally designated by the numeral 7. See Figs. 1 and 3. This regulator includes two inverted bells 7 and 7" which are so positioned within a liquid receptacle 7 that'their lower edges are sealed by the liquid within the receptacle. These bells are mounted on alever 7 which is fulcrumed at aninter mediatepoint between them andwhich controls the operation of a relay 7. The branch 14: of the piping 14 projects up bottomfof the rece Jta-cle 7 into the interior of the bell 7 so that it terminates well above the level of the liquid within the receptacle. The movement of the hell 4, and consequently of the lever 7 in re sponse to variations ofpressure within. the bell 7 is controlled by an adjustable spring 18, which is operatively connected to an extension 19 of the lever; The bell This open to the atmosphere througha pipe 7", which extends up through'the bottom of the receptacle 7 and is provided below the receptacle with a valve for restricting itsefiectivearea.

WVith this arrangement,tlie bells and their supporting lever move to different positions in response to variations in the pressure transmitted through the piping .14, the movement being resisted or assisted by the tension of the spring 18. It will be under- 1 stood that the hell 7" merely functions as a means of a pressure plunger,

dashpot and prevents excessive movements of the lever. i

Each primary regulator 7 also includes a relay cross-head 20 which is operated by as described in connection with the master regulator, and which cont-rols the delivery of fuel to its associated boiler furnace and also imposes a controlling effect on the delivery of air to that furnace.

As shown diagrammatically, the crosshead 20 is'operatively connected to a rheostat 21, which indirectly controls the delivsystem.

er of current to the coal feeding motors 22. Thisls accomplished by employing a Inotor-actuated relay 22 for thesemotors which is actuated'by a reversing motor 22 controlled by therheostat 21.

As I have stated, the diagrammatic illus' tration contemplates employing powdered {coal asfuel; therefore, the motors 22 may operate coal pulverizmgandconveying apparatus or they'inay merely operate coal conveying apparatus, the intent being to vary the delivery of fuel to each boiler furnace so that the rate of delivery corresponds to variations in steam pressure within the steam header fed by all the boilers of. the

In order to insure prompt response to the automatic control, it is desirable to directly proportion at least a part of the air supply 1 tothe furnace, to the rate of fuel feed, and

consequently I have illustrated the cross head 20 as directly connected to a damper 23which controls the delivery of secondary air through the fuel feedflburner diagrammatically illustrated at 2%. See Fig. 1. It will, of course, be understood that each boiler furnace will preferably be provided with a plurality of such burners, as is customary in powdered fuel installation of today, and that the relative proportions of air delivered through the air passages of the burners may be proportions to suit conditions encountered. From the foregoing, it will be apparent that variations in th'e'steam pressurewithin the steam header receiving steam from all the boilers of the system will occasion variations l'ii air pressure within the piping 14 and consequent-lywithin the bells 7 of the various primaryregulators 7 and that thecross-head's Q0 of these regulators will therefore move 'to ditferent'positions and vary the rate of fuel delivery in the mafnner described. For example, areduction in steam pressure will occasion an increase in the air pressure within the bell 13 by reason of the fact that the master regulator will, under such conditions, operate to lower the bell and increase the effectiveness of ithev sealmg liquid around the lower edgeof the bell. This will increase thepressure within the bell 7 and cause it to move, in opposition to the tension of the spring 1.8, and "will thereby occasion at raising of the cross-head 20 which will increase the speed of the fuel feeding motors and will also increase the delivery of such portion ofthe combustion air as'is delivered through the fuel feeding burners.

Each primary regulator 7 also imposes a control on the delivery of such additional air to its associated boiler furnace as is necessary to obtain complete combustion. It will,

of course, be apparent that operating conditions may vary. in each of the furnacesdue to variations in the conditions of the furnace and the gas passages thereof and that it is therefore desirable, and in fact necessary, to control the delivery of the major portion of the air to each furnace in such a way that it is not only responsive to the varying rates of fuel feed but is also responsive to the conditions obtaining within the furnace and the gas passages thereof. In other words, it is not sufficient to merely actuate the air delivering or controlling apparatus so that its operation varies with the rate of fuel feed, since conditions within the furnace or within the gas passages of the furnace may be such as to necessitate a further adjustment of the air delivering or controlling apparatus in order to compensate for variations of conditions encountered therein.

In the apparatus illustrated, I control both the input and the withdrawal of air from each boiler furnace, and while this control is primarily responsive to the operation of the associated primary regulator, itis also modified by conditions which are or may be independent of the pressure of the:

steam within the main header.

As shown in Figs. 1 and 3, the primary regulator controls the operation of a seetil i ondary regulator 25 which actuates a damper 26 located between the boiler furnace and the stack. The adjustment of this damper is, however, controlled through the secondary regulator by the joint action of the primary regulator and of the pressure existing within the furnace passages immedlately ad acent to the damper 26, but on the furnace side of that damper.

This is accomplished by employing a regulator mechanism, similar to the mechanism described in connection with the master regulator 6 in which the pressure chamber 8 is directly connected to a flexible tube 62 which contains a column of liquid such as mercury and is soconnected to thecross head of the primary regulator 7 that variations in the position of that cross-head 20 occasion variations in the head of the liquid contained within the tube and consequently occasion variations in the effective pressure within the chamber 8 The pressure-responsivcelement of this chamber is operatively connected to a pivoted lever 9, which controls the operation ofa relay cross-head in the manner heretofore described. The effect of the pressure in the chamber 8 on the lever 9 is opposed or modified by a bell 25", operatively connected to the lever. As shown, the bell is inverted and extends into a liquid receptacle such as is above described,

. and piping 27 projects through the bottom of the receptacle and into the interior of the bell 25 above the sealing liquid contained within the receptacle.

This piping is in open communication with the gas discharge passage or the breach ing 28 of the boiler furnace 29, the point of communicationbeing on the furnace side of the damper 26, which is located within the passage 28. Under such conditions, variations in pressure within the passage 28 will impose a controlling or modifying effect on the operation of the regulator 25, with the result that the cross-head 25 will respond to the composite effect occasioned .by movements of the primary re ulator 7 and by variations in pressure'at the furnace side of the valve 26.

It will, of course, be understood that under normal operating conditions a negative pressure, i. e. a pressure below atmospheric pressure, is encountered in the offtake passages from the boiler furnace and that, therefore, the pressure within the bell 25 will be less than atmospheric pressure, withthe result that this negative pressure will, to some extent, offset or counterbalance the positive pressure occasioned by the column of' liquid contained within the tube 62*.

With this arrangement, the rate of fuel delivery to each boiler furnace 29 will vary directly in response to variations in steam pressure and the secondary regulator will adjust the positionof'the damper 26 so as to maintain the proper conditions within the ofl'take passages of the boiler furnace for the rate of fuel feed encountered.

The delivery of the major portion of air for combustion is also controlled by the primary regulator 7, but the effect of this regulator is so modified by conditions within the furnace as to provide the requisite air suply for complete combustion of all the fuel delivered even under the varying conditions which may be occasioned by the particular installation or the varying conditions of the apparatus employed as a part of the installation. I

As shown, the cross-head 20 of the primary regulator 7 is operatively connected to a lever 30, fulcrumed at 30' and from which a bell 30 is suspended. The lower edge of this bell is submerged in a liquid contained within a rece tacle 30 and a restricted flow of air from t e piping 13 or from a source of suitable pressure is delivered to the interior of the bell through piping 13 The pressure of this air is greater than that which can be sealed by the. sealing liquid within the receptacle 30. Piping 31 communicates with the interior of the bell 30 and there fore'transmits a pressure which is directly proportional to the position of the bell with relation to the level of its sealing liquid in the receptacle 30 This pressure is transmitted through a branch pipe 31 to a forced draft regulator 32 whiclLma-y be of the conventional form described in connection with the primary regulator 7. As shown, the

regulating lever 32 of this regulator is provided with two inverted bells 32 and 32,

each of which projects into a sealing liquid contained within a suitable receptacle. The pressure carried by the branch ipe 31 is introduced into the interior of t e bell 32* and the pressure delivered by a forced draft fan 33 is introduced into the interior of the bell 32 through piping 33; The relay crosrhead is operatively connectedtothe control valve 34 of the engine (not shown) driving the fan 33, and the arrangement is such that as the pressure decreases within the piping 31-31, due to a reduction in the steam pressure, the relay33 will move to admit more steam through the valve 34 of the driving engine of the fan and therebyincrease the delivery of forced draft to the furnace 29.

As diagrammatically shown, thefan 33 delivers air through a preheater35 and then through a passage 36 to the air inlet ports 29 of the boiler furnace. In order to insure the proper delivery'of air, in response to the variations occasioned by the operation ofthe primary regulator 7, and independently of the conditions which may exist in the preheater 35 orconnecting passages, the piping 33 communicates with the passage 36 on the furnace side of'the preheater. NVith such an arrangement, the speed of the motor driving the forced draft fan will be determined by the steam pressure in the main header as modified by conditions encountered within the air delivery passage 36, with theresult that the position of the cross-head 20'will not actually determine the speed of the forced draft fan but will merely insure such an operation of the fan as may be necessary to furnish sufiicient air for oc'casioning complete combustion at the rate of fuel feed encountered. V y

The delivery of air to the furnace is, however directly controlled by the conditions,

within the combustion chamber of the furnace. This is accomplished by providing a damper 37 in the passage 36 and by em ploying a regulator,38,responsive to combustion chamber pressure, for controlling the operation of that damper.

As diagrammatically shown, the damper 37 controls the delivery of air through ports 29 formed in a wall of the furnace 29 in ac cordance with the approved. practice employed in connection with powdered fuel firing. It will, of course, be understood that a number of dampers may be employed for controlling the delivery of air through the wall ports, and that it is not essential to my invention that this air be preheated or even that it be delivered under pressure,although it is necessary to proportion its delivery to the rate of fuel feed.

As shown, the regulator 38'is oftlie type illustrated and described in connection with the primary regulating apparatus? and includes two inverted bells 38 and 38 which regulator 38. v

dashpot for checliing the movements imparted to the lever by the bell 38. The air rangementis such that, as the pressure increases within the combustion chamber, the bell 38 responding to the increase in pressure swings the lever, and this in turn moves the' cross-head 38 to closethe damper an amount corresponding'to the increase in pressure, andvice versa. From theforegoing, it will be apparent that the delivery of a portionof the air to the combustion chamber is controlled directly by the primary regulator 7 and'that the delivery of the remaining portion is ie do sponsive to variations in steam pressure as modified by the pressure within the combustion chamber and communicating discharge passages. This dual control is occasioned by thefactthatthe adjustment of the damper 05 23 controlling the air flow through the ports 24, forming a part of the fuel feed burner,

is controlled directlyby the primary regulator7, since the adjustment of the damper 23 depends solely upon the positioning of the 1510 relay cross-head 20; Whereas the additional air delivered to the furnace is responsive to the combined effect of the variations in steam pressure as modified h pressure conditions within the furnace an furnace passages as impressed on the re ulators 25, 32 and 41, and as further modi edby the action of the In the diagrammatic illustration, I have shown aninduced draft fan it) for removing no waste gases through the gas passage 28.

flhis fan is controlled by the combined effect of the regulator-adjusted air pressure delivered through the piping 31 and of the reduction in pressure occasioned by the opera H5 tion of the fan lt) and the iuirticular adjustment of the damper 26 in the waste gas passage 28. As shown, the adjusted air pressure from the bell 30 of the primary regulator 7 is delivered to an inverted bell 4L1 of a regu- 110 lator 41. This regulator is similar tothe regulator 32 shown in connection with the forced draft fan, except that the bell 41 is divided into two conmartments, one of which receives the'air pressure introduced through the branch pipe 31 and the other of which forced'draft fan as the cross-head 41? moves lnresponse to a decrease in the pressure delivered through the branch pipe 31". It will, of course, be apparent that the pressure de livere'd through this pipe is counterbalanced by the reduced pressure communicated through the piping 42, and thatjconsequently, the operation of the fan is controlled by the pressure in the waste gas offtake 28 and in the piping 31 from the regulator 7. In other words, it may be said that the induced draft fan operates in response to "ariations in steam pressure, as modified by variations in pressure encountered within the passage 28. It will also be apparent that these last variations referred to are dependent not only upon the speed of the fan but also on the adjustment of the damper 26, with the result that the operation of the fan 40 is modified by the drop in pressure across the damper-26. It will also be apparent that the pressure within the passa e 28 will also depend upon the rate of combustion within the furnace.

Both of the regulators 32 and 41 are provided with adjustable springs 43 which are so arranged as to oppose the movement in one direction of the associated levers and that therefore the automatic operation of the two fans may be adjusted or varied at will by changing the adjustment of these springs.

Attention is also called to the fact that each primary regulator 7 is,like the master regulator, provided with means for rendering it non-automatic or for rendering it a manually controlled mechanism. As shown in Fig. 3, the regulator 7 is provided with a bracket 44 which straddles an extension of the lever 7 and which is provided with oppositely projecting thumb screws 44 and 44 adapted to engage opposite sides of the extension and therefore hold the lever in a definite adjusted position in the manner described in connection with the master regulator. These thumb screws and the bracket 44 are however so positioned that they will not interfere with the normal swing of the lever 7 when the screws are adjusted for automatic operation of the regulator 7 From the foregoing, it is apparent that the entire operation of a boiler plant may be controlled automatically by the master regulator 6, and under such conditions that the rate of fuel feed to each boiler furnace of the controlled group willvary in response to V variations in the steam pressure. within a header fed all of the boilers ofthe group. It will also be apparent that a portion of the air for combustion will be controlled directly in response to the variations in this steam pressureor to the variations in the rate of fuel supply, but that the remaining air de livered to each boiler furnace will be proportioned in accordance with conditions encountered within the furnace and the waste gas passages thereof.

It will also be apparent that the entire group of boilers may be manually controlled by means of the thumb screws associated with the bracket 16 of the master regulator or that any of. the boiler furnaces may be manually controlled by means of; thethumb' screws 44 and 44" of the primary regulators while some of the boilers of the group are responding to the automatic control initiated by the master regulator. It will also be apparent that the conditions of automatic control may be varied materially or adjusted for each furnace byvarying the adjustment through one of a number of suitable passages 24 which communicates with an auxiliary air duct 46 in which the air pressure is pro portioned to the rate of fuel delivery.

As shown, the auxilia'ry air duct 46 communicates with a primary air duct 47, which receives air under pressure from a fan 48. One or more such fans may be employed depending upon the number of furnaces con-' stituting the unit. The driving engine (not shown) of the fan 48 is controlled by a regulator 49 which is similar to the regulator 32 and which controls the opening and closing of the engine valve 50. As shown, the regulator 49 is provided with two inverted bells 49 and 49", both of which are sealedby a sealing liquid a's'previously described. The interior of the bell 49 receives air under pressure from the master regulator through. the piping 14 and a branch pipe 14". The

, effect of this air pressure is counterbalanced,

by delivering air to the interior of the bell.

49 through piping 49 which communicates with theprimary air duct and is in open (pressure of the fuel conveying communication with the delivery port of the fan 48. The regulator 49 is also provided with an adjustable control spring 43, and the V arrangement is such that a decrease in steam presrasurc, reflected by the master regulator by a corresponding decrease in the pressure delivered through the line 14 and 14*, will occasion a speeding up of the fan 48,but the speed of the fan is modified by the pressure air duct 4Gfor each boiler furnace of the controlled group, and as will be described,

the delivery of fuel conveying air to each furnace is proportioned to the rate of fuel delivery to that furnace. In the apparatus illustrated, this is accomplished by controlling the delivery of air to'each auxiliary duct 46 by means of a regulator 51 which responds to the operation of the primary regulator 7 associated with the particular boiler with which the auxiliary air duct 46 is associated.

As shown, communication between. the

auxiliary air duct 46 and the main duct 47 for fuel conveying air, is controlledby the regulator 51 in responsetothe operation of the particular primary regulator 7 with which it is associated, and which in turn controls the operation of valves 52 between the primary air duct and the duct 46. The regulator 51 may be similarto the regulators heretofore described and is provided with two inverted bells 51 and 51" mounted on a pivoted lever and having their inte riors sealed by a'sealins fluid. These inverted bells also eontrolthe operation of a pressure-actuated cross-head 51 which is operatively connected to the valves 52. The interior of the bell 51" communicates through piping 51 with the interior of a bell 53 which is mounted on the lever forming a part of the primary regulator 7, and the bell 51 is mounted on the opposite end of said lever and its interior isqsubjected to the pressure within the auxiliary duct 46 through piping 51. y

The bell 53 is suspended by a suitable link from the lever 30, which aspreviously described, is actuated by the cfoss.-head 20 of the associated primary regulator 7. The lower edge of thisbell extends into a seal-' ing liquid contained within a receptacle 58' and air under pressure is delivered to the interior of the bell through a branch pipe 13 from the pipe 13", in the manner de-' scribed in connection with the bell 13 of the master regulator. The'depth of the sealing liquid contained within the receptacle 53 is not sufficient to seal the pressure introduced to the interior of the bell through the pipring 13 and consequently theair prcs'ssure within the bell will vary withthe position of the bellrelatively to the surface of its sealing liquid. This adjusted pressure varies with variations in the position of the cross-head 20tand consequently with variations in the steampressure controlling the master regulator 6. The pressure within the bell 53 is delivcredtto thebell 51 through the piping 51 and, as a result of this, the regulator fil will respond to variations in steam pressure as modified'by the operation of the master regulator 6 and the associated primary regulator 7 In addition, the opera tionof the" regulator 51 is modified by the air pressure within the-auxiliary air duct 46,-with which it is associated, by reason:

of the factthat the piping 51 delivers this airpressure to the interior of the bell5l It will, therefore, be apparent that as the demand for an increased rate of fuel feed occurs, the regulator 51 will tend to open the valves 52 and increase the delivery of air from-the primary air duct to the secondary air duct 46 which supplies fuel conveying air to the associated fuel feed burners.

This tendency is subjecti'to the modifying effect of the air pressure within the auxiliary duct which, to some extent, is dependentupon conditions within the associated furnace; but under normal operating conditions, the regulator 51 will operate to increase the rate of delivery of the-fuel conveying air as the rate of delivery of fuel is increased in response to decreasing steam pressure within the header supplied by the boilers of the controlled unit; i

As diagrammatically shown, the sealing liquid receptacles forthe bells 51*, 51 and 49 areespecially formed to receive a heavy sealing liquid such as mercury, and it will be apparent that various modifications such as these my be employedthroughout the installation without departing from the spirit or scope of this invention, since I. am not primarily concerned with the type of regulators employed nor with the specific details of their construction. The broad underlying principle of my invention is to so control combustion conditions within the verb ous furnaces included in the systen'i as to obtaineflicient operation of each of the furnaces and at'the same time a co-ordinzttion of all thefurnaces which will uniiorm-v ly distribute the load on the different boilers and will automatically maintain thedesired tion thereo't' associated with anindividual boiler may be rendered non-automatic so that all or any one of the boilers may be placed under the direct control of an attendant for the purpose of establishing the desired conditions.

\Vhat I claim as new and desire to secure by Letters Patent is:

1. Asteam generating system, comprising a plurality of steam generators, a common header receiving steam from said generators, and an individual furnace for each.

generator, fuel feeding mechanisms for each furnace, air supplying mechanisms for each furnace, a separate regulator responsive to variations in steam conditions within said header for controlling the operation of each furnace, a regulator responsive to variations in steam conditions within said header, as reflected by. said first mentioned regulator and as modified by pressure condigenerator, fuel feeding mechanisms for each furnace, air supplying mechanisms for each furnace, a separate regulator responsive to variations in steam conditionswithin said header for controlling the operation of each furnace, a regulator responsive to variations in steam conditions within said head er, as reflected by said first mentioned regulator and as modified by pressure condi tions within'the air delivery'passages to the furnace for controlling the operation of said air supply mechanisms, a regulator responsive to variations in pressure within the furnace for controlling the delivery of a portion ofthe air from said air supplying mechanisms to said furnace, and means actuated by said first mentioned regulator for controlling a portion of the air supply to the furnace.

3. A system of control, comprising a plurality of steam generators, a steam header receiving steam from said generators, an individual furnace for each generator, fuel feeding mechanisms for each furnace, airdelivery mechanisms for each furnace, a master regulator responsive to variations in steam pressure within said header, a fluid distribution system, means actuated by said regulator for occasioning pressure variations in a fluid distribution system responsive to the variations in pressure within said header, a separate regulator responsive to variations in fluid pressure within said system for cont-rolling the operation of each fuel feeding mechanism, and a separate regulator for controlling the operation of each air individual furnace for each generator, indi-v vidual fuel feeding mechanisms for each furnace, individual draft X'tfglllntlllglDOClL aiiisnis for each furnace, at 11135513?! regulator responsive to variations in steam pressure within said header. a fluid distribution system, means actuated by said regulator for oc- CHSIOIHIIgPI CSSUI'G variations in said distribution system corresponding to variations I in pressure insaid lieader,-a primary regulator associated with each furnace and subject to said pressure variations, a separate regulator "for each furnace responsive to said primary. regulator and to pressure variations within said system for controlling the 7 fuel feeding mechanisms of the associated furnace, and a separate regulator for each furnace responsive to pressure variations within'said system forcontrolling the associated draftregulating mechanisms and. responsive to the draftthe associated furnace.

5. A systeinof furnace controLincluding a plurality of steam generators, an individual furnace associated with each generator,

a-steani header receiving steam from all said generators, individual fuel feeding mech-. anisms for each furnace, individual air supplying mechanisms for each furnace, individual draft control mechanisms for each furnace, a primary regulator for each furnace responsive to variations in steam pressure within said header for controlling the delivery of fuel to the associated furnace, a secondary regulator for-each furnace responsive to the operation of said primary regulator and to the pressure within the waste gas passages oftlie furnacefor controlling the operation ofv said draft regulating mechanisms, and a regulator responsive in oper ation to the operation of said priinar regir lator and to the pressure delivered y said air supply mechanisms for controlling the operation of said air supplying mechanisms.

6. A system of furnace control including aiplurality of steam generators, an. individual furnace for each generator, a stcam line receiving steam from all the generators,

a master regulator responsive to variations in steam pressure Within saidline, a fluid distribution system, means-actuated by 331d regulator for occasioning variations in fluid pressure within saidsystem, aprimary regulator associated with each furnace and responsive to variations in feeding mechanisms for each furnace responsive to the operation oisaicl primary pressure supplied i to ressure within a said distribution s stem, individual fuel emma regulator, a separate secondary regulator for each furnace responsive to the operation of said primary regulator and toivariations in draft pressure ofthe associated furnace, draft regulating means controlled by said secondary regulator, individual air supplying mechanisms for each furnace, and a regulator responsive to variations in fur nace pressure for controlling the delivery of air from said air supplying mechanisms to the associated furnace.

7. Asystem of'furnace control includin a steam generator, a furnace associate therewith, a steam header receiving steam from said generator, a master regulator responsive to variations in steam pressure within said header, a fluid distribution sys term, means actuated by said regulator for occasioni' variations in fluid ressure within s stem, a primarylregu ator re-' sponsive to uid pressure variations Within said 5 ste n, fuel feeding mechanisms for said urnace controlled by, said primary regulator, a second fluid distribution system,

means actuated by said primary regulator for .occasioning {variations in fluid within said second s' stem, air. mechanisms for said urnaoe, a regulator res nsive to variations in pressure within sai second system and to variations in pressure delivered by said air delivery. mechanisms for controlling said air delivery mechanisms, draft controlling mechanisms, and a regulator responsive to variations in fluid pressure within said second distribution system and to. variations in draft pressure draft controlling mechanisms.

8 A system of furnace control, comprisin a lurality of steam generators, anindividual furnace for each'generator, a steam gressure elivery header receiving steam from all the generators, individual fuel feeding mechanisms for each furnace, individual forced draft mechanisms for each, furnace, individual induced draft mechanisms for each furnace, a master regulator responsive tovariations in steam pressure within the header, a prima regulator for each furnace res onsive to t e operation of said :masteriregu ator in controlling the fuel feeding mechanisms of the associated furnace, a separate reg ator for each furnace responsive inoperation to the associated primary regulator and controlling the forced draft mechanisms of the associated furnace, -and an induced draft regulator for each furnace responsive n operation to the associated primary-regulator for controlling the operation of said induced draft mechanisms of the associated furnace; a j 9. A system of control for a pulverized fuel burning furnace, comprising a steam generator, a furnace associatedtherewith,

twat: ilmmwsum or controlling the operation; of said ulators, an means associated with eac pulverized fuel feeding mechanisms, forced raft delivery mechanisms, induced draft delivery mechanisms, fuel conveying air delivery mechanisms, a regulator responsive to variations in steam pressure delivered by said generator, and separate cooperating regulators responsive to said first-mentioned regulator for controlling each of said mechanisms. a

10 A system of furnace control including a plurality of steam boilers, a separate furnace for each boiler, aseparate means for delivering fuel to each furnace, separate means for delivering air to each furnace, a separate regulator for controlling each such means, a separate primary regulator associated with each furnace, means [controlled by said primary regulator for controlling the delivery of actuating fluid'to each of said first mentioned regulators, adjustable means associated with each of said first mentioned regulators for independently varying "the effect of the actuating pressure delivered thereto. a

11. A system of control for a plurality of boilers, all delivering steam to a common header, and each provided with a furnace, a separate regulator for each furnace for controlling the supply of air thereto, a separate regulator for each furnace for controlling the supply of fueljthereto, a primary regulator for each furnace responsive in o eration 'to variations in the steam suppy 12. In a s stem. of boiler control, a plu rality of boi ers to be controlled, a separate furnace for each boiler, a plurality of regulators associatedwith'each furnace for separately controlling combustion conditions therein, a primary regulator associated with eachfurnace for controlling the other regulators associated therewith, a master regulatorresponsive to variations of steam supply delivered by all of said furnaces, means acturegprimary regulator for varying or rendering inatedthcreb for controlling allprimary effective the control of said master re ulator.

13. In combination in a system 0 boiler control, a boiler, a furnace therefor, means for 'oontrollin the draft of said furnace means for delivering fuel to said furnace,

means for controlling said first-mentioned means in accordance with variations in the rate of fuel fed by said fuel deliver means, means responsive to variations in t e steam suppl deliveredby said boilerfor controlling t e delivery of air to said furnace, and

means controlled b the pressure within the furnace for contro 'ng the delivery of additional air to the furnace. 1

14. In combination with a boiler furnace, means for deliveri o pulverized fuel to said furnace, means for elivering fuel conve ing air to said furnace, means for contro ing said air delivery means to maintain a predetermined air pressure, and means for proportioning the pressure of the fuel conveying air delivered to said furnace in 'accordancewith variations in the rate of fuel feed.

15. In combination with a boiler furnace, means for delivering pulverized fuel thereto, means for delivering fuel conveying air to said furnace, and means for varying the pressure of the fuel conveying air in accordance with variations in the rate of fuel feed thereto. 7 y

16(In combination with a boiler furnace, means for delivering pulverized fuel thereto, means for deliveringfuel conveying air to said furnace in response to variations in steam pressure delivered by the boiler, means for varying the pressure ofthe fuel conveying air in response, to variations in steam ressure delivered b the boiler, and means or controlling the livery of air for combustion to said furnace in accordance with draft conditions within the furnace.

17. In combination in a control system, a regulator, means for delivering actuating fluid pressure to said regulator, comprising an open end bell, having its open end submerged in a sealing liquid, means for delivering fluid to said bell at a pressure greater than can be sealed by said liquid, means for deliveri'n fluid pressure from said bell to said regu ator, and means for varying the position of said bell with relation to the .sur

face of said sealing liquid to vary the pressure of the fluid so delivered.

'18. A system of boiler control including a boiler and furnace therefor, comprising a fan for delivering air for combustion to said furnace, a regulator for controlling the operation of said fan, a second regulator responsive to variations insteam delivery from said boiler, means actuatedb said second regulator for controlling the delivery of actuating fluid pressure to said first regulator and means associated with said first re ulator for counterbalancing said actuating d uid by air pressure delivered bysaid fan.

19. A s stem of boiler control including a boiler and a furnace therefor, comprising an air duct from which air is delivered to said furnace, a regulator for controlling the pressure of the air Within said duct, a second regulator, responsive to variations in the steam supply delivered bysaid boiler, means actuated by said second re ulater for varying the actuating pressure eli'vered to said first regulator, and means associated with said first regulator and receiving air pressure was 20. A system of boiler control including aboiler and a furnace therefor, com rim'ng m a plura-lit of regulators for separate y controlling t e forced draft, the induced draft and the delivery of fuel said furnace, a master'regulator, responsive variations in steam supply in a header receiving steam from said iler, a prima regulator, means controlled by said ma er regulator for deliver" actuating pressure to Said rimary' regu ator, and means controlled y said primary regulator for delivering actuating pressure to said plurality of regulabors. a 21, A system of boiler control includ ng a boiler and a furnace therefor, nsrng a'pluralit of regulators for fiPatate controlling elivery of fuelanddraft {ions within giiid furnace, means ivering varia ecactuati ressure .ea of regulators, a priliifiigr re 7 ator controlling said means and re' QSIVBUQ varrations'in steam supply'wi "aheader receiring steam from said boiler," and 'gneans associated with each of said pfnralrty of regulators for subjectingeach ,such 'regu- A later to a variable pressure by the regglator subjected to such control. p j A system of boiler control including a boiler and a furnace therefoncomprising a plurality of regulators "for separate 3 controlling the delivery offuel and fimfiratt condlitions within said f rnace, a pal ngary reguatonherislponsive to steam con trons within 2. er fed by sqid'boiler, means,

controlled by saidprllpaiw r g rr delivering actuat ng. fluidl lressnre to each of said first-mentioned r ators, Y and means asociated with who said regulatons for snh'ecting the samelto the influence of a secon fluid pressure variable in re- 7 sp'onse to the operation of the regulator 23. In combination in asystem of boiler -furnacecontro1,'a plurality oi'boiler furnaces all delivering steam a common header, fuel and air-supply meassociated with each regulators (for controlling the operation ofisalid mechamsms, a primary I each furnace for controlling the-operation of said filst named regulators, and'a mastar regulator responsive to variationslin the pressure in said header. for controlling the operation of Said primary'regilatois.

regulator with '24. .In combination innasydem of boiler;

furnace control, a plurality 6f boiler .fnrnaces delivering steam to a common header,

fuel. and air-supply mechanisms associated with each furnace, regulators" for "controlhug the operation of said mechanisms, a primary regulator associated with each furciated with each furnace, regulators for controlling the operation of said air-supply mechanisms, a primary regulator associated with each furnace for controlling the operation of the associated fuel-supply mechanism, connections whereby the operation of each of said first-named regulators is controlled by the associated rimary regulator, and a master regulator 2 operation of said primary regulators.

or controlling the 26. In a system of boiler furnace control, a plurality of boilers to be controlled, a

arate furnace for each boiler, a plurality of regulators associated-with each furnace for separately controlling combustion conditions therein, a primary regulator associ ated with each furnace for controlling the other regulators associated therewith, a masster regulator responsive to variations in steam supply delivered by all of said furnaces for controlling the operation of said primar regulators and means for manually contro ing the operation of said master regulator independently of said variations in steam supply.

In testimony whereof, I have hereunto subgcribed my name this 21st day of July, 192

THOMAS A. PEEBLES. 

